High-speed-screw jack



July 20 1926. 1,593,364

F. H. SCHWERIN HIGH SPEED SCREW JACK Filed August 35', 1923 3Sheets-Sheet 1 I E] venioz I v ZWA 3 M 35 3 6W7 July 20,1926. 1.593364F. H. SCHWERIN HIGH SPEED SCREW JACK Filed August 25. 1923 3Sheets-Sheet 2 avwewcoz F. H. SCHWERIN HIGH SPEED SCREW JACK July 20,192 6.

3 Sheets-Sheet Filed August 25, 1923 39 36 .35 v avwnto'c 351g @lfliovmJuly 243, i925.

mart stares teases? this FRANK sonwniam, or WEST VEEW, renusvnvaumassreuon TO THE DUFF e or PENNSYLVANIA. V

This invention relates to the class of screw lit ing jacks known ashigh-speed jacks havrag screws of suiiic iently steep pitch to run downunder the load. Various "forms of high-speed jacks are known and theteatu'res of the invention are not necessarily limited in theirapplication but are illustrated in connection with the jack disclosed inthe Kept & Schwerin Patent No. 1.329,- 665 of February 3, 1 920, forwhich they have been more particularly designed. The ohj'ectfi's,therefore, to provide certain tea tures of improvement whereby greaterstrength and increased ei'licieno'y and con ven'ience are secured.

fine of the features is an improved construction of the overrunningclutch between. the holding and lowering mechanism and the steep-pitchscrew, another feature is an improved construction for he manuallyoperatable el'ut'cl'i whereby the. lowering means can becoupl'ed withthe screw for r positive lowering of the jack when without load, andstill another feature has to do with an attached lowering handle, whichis connjactly disposed when not in use.

In the accompanying drawings forming part hereof: v

Fig. 1 is a view, partly in elevation and partly in central verticalsection of a aclt embodying the improvements;

Fig. 2 is a large fragmentary vertio'alsectional view looking at rightangles to Fig. 1, the vertical shaft in the plane of section being'shown partly inelevation and partly broken away and in section;

Fig. Sis a detail view or an operating plui'i'ger and crosspin;

' Fig; e is an enlarged horizontal section onjthe line of Fig. 1;

Fig. 5 is a fragmentary elevation on an enlarged scale looking at theback of Eig. 1', and showing the lowering handle folded st the frame and45 g, Sisa fra t s ctional elevation le sho g; the handle Otjt l in d I1me and rises upward within MANUFACTURING oomrnur, or P TTSBURGH,snmrsvrivaurn, A ooaroaarrou HIGI-I-SPEED-SCREW JACK.

Application filed August 25, 1923. serial No. 'esaee rain 3, whichcarries a nut or hollow screw member 6 for cooperation with the screwFastened on the'lower portion of the screw is a large spur gear 7, whichrests upon ball-plates 8, 9 and interposed balls 10. The gear 7 ismeshed by a pinion Lion the lower end ot a vertical shaft 12, which is journ'aled in bearings 13, 14 and 15 in an annex 16 of the base trains.

Fast on the shaft 12, above the pinion 11, is a bevel gear 17, which maybe termed the lifter gear. This gear is meshed by a bevel pinion 1 8,whic'ln as shown in the Kop't S: Schwerin patent referred to, isoperated by a long removable bar-lever 19 through oscillatory pawl andratchet mechanisnn which it is not thought necessary to show here indetail since such matters arewell known.

A ratchet wheel 20 is fixed to the shaft above the bearing 1 k, and thisis surmounted by a pawl-carrier wheel '21, which is rotatable on theshaft and has depending rini portions '22, which are opposite theperiphe'ry ot' the ratchet wl'ieel. In the intervals 28 between thesesaid portions 22 are pawls 24, preferably three in n'ijunber, pivoted onpins 25 to engage with the teeth of the ratchet wheel, which havesloping backs, so that the two parts of the overrunning clutch thusconstituted are free to rotate relatively to each other in one sense ordirection while having" driving or holding engagement in the reversesense. One of the features of the ihv'ention has to do with thisoverrunn'ing clutch, which is interposed between the shaft 12, andtherefore the SCIQV, on the one hand, and the holding and loweringmeans, to be described, on the other hand.

It will be seen in Fig. e that each of the pawls 24 is provided with atail 26 projecting rearward from its pivot, that is to say reversely tothe body of the pawl. The riin portions 22 of thepawl-carri'er 21 arearmed to allow clearance for these tails, aiid are -"ovided with seekers27 in their hare opposite the inner sides of lls. The tails themselvesare Irostuds 28 projecting from tfiei'r sockets, and com Sebeoi1spririgs 29 re entered iILthe are 27 with their outer ends engagedover ehejstuds '28} These s rings constantly depress the so to bear uponthe ratchet wheel, the construction being such as to avoid the operationof the jack being impaired or destroyed through the failure of thesprings of the overrunning clutch. The ends of the bodies of the pawlsare preferably formed with two teeth 30, instead of one tooth asheretofore.

The holding and lowering means is prefcrably, though not necessarily, ofthe kind comprising a worm wheel 31 meshed by a worm the pitch of thegear being such that the wheel 31 which encircles the shaft 12 can notdrive the worm 32. Consequently. if the wheel 31 is connected with thelifting screw, the load can not descend unless the holding worm isrotated in the proper direction. The jack is nevertheless virtually selflowering in the sense that the weight or the load drives the jack downand operates all the mechanism up the holding device 32. which is simplylet off by hand. The advantage of this particular form of holding" andlowering means is safety, since the jack can not run away or start downunintentionally.

As shown, the worm wheel 31 is united with the pawl-carrier 21, and thearrange- .ient of the overrunning clutch 20, 21, Ed is such that thescrew 5 and the shaft 12 geared thereto can be operated by the lifting'lever 19 for lifting without rotating the worm wheel 31, that is to sayinde pendently of the holding and lowering means. At the conclusion ofeach lifting movement. however, descent is prevented through thepositive engagement of the parts of the overrunning clutch so that theeffort exerted by the load is transmitted to and res -tted by theholding means.

The worm 32 occupies a lateral boss or enlargement 33 on the frame annex16, and its shaft or journals are mounted in suitable hearings. one ofwhich is a gland 3.4 screwed into the outer end of the boss 33containing a bearing 35 for the journal end 36. A. crank handle. 37constitutes the means for manually rotatingthe lock or holding device32, so as to permit the jack to lower. The same handle can also be usedfor rapidly running the jack up to the load. Heretofore this handle hasbeen a separate piece, adapted to he Focketed to the journal end of theworm. and for this reason it has not als been at hand when needed. andin the present improven'ient an elbow 38 is pinned it 39 to the journal36 so that its outer 'iortion -t0 projects at right angles to its avialportion. The end of the bentportion i0 is bifurcated and receives theinner end of the crank handle proper 37. A pivot pin 41 passedtransversely through the parts of this region rigidly connects thehandle proper and the elbow for rotary operation, and permits the handleto be folded over the hos 33, where it will be confined by a projectingfrom the top of the boss ear the wall of the annex rising above boss,seen in Fig. In the operaposition the shank of the handle proper 15-.turned outward, so as to form a continuation of the bent portion 40 ofthe elbow. Curved notches l2, :1 quadrants distance apart on the hub 43of the handle proper 37. cooperate with a non-positive locking plungerll pressed from a bore if) in the elbow portion it) by a spring it), sothat the handle held tirmly, though yieldingly, in each of itspositions. The folding construction of the crank handle of the loweringworm not only connects the handle p rm nently to the jack frame, whileenahlin y it to be folded compactly out of the way against the frame,but also has the fur ther advantage that if the handle should be leftunfolded while the jack is wheeled about in a rearwardly tiltedposition, the handle will not become bent or interfere with the\i'heclingby coming in contact with the around. it will be seen in Fig.1 that if the jack should be tilted backward so that the end of thehandle bore forcibly against the ground, the pivotal joint -ll would automatically bend in a perfectly safe manner. lVere it not for thisjoint, the handle or the loweringmechanism controlled thereby might.easily be injured so as to render one of these large jacks, which areused for jacking: up locomotives and heavy cars, either inoperative orunsafe.

lVhile the jack runs down by gravity, as permitted by manipulation ofthe holding and lowering means, it is nevertheless desir able to providemeans for positively lowering or driving down the jack in case theweight of the lifting member alone, when the jack is unloaded, shouldnot be sutiicient to overcome friction, or in case at any time stickingmight occur when it is desired that the load member shall be set. Forthis reason means are provided, as in the Kopf & Schwerin patentaforesaid, for positively coupling the rotary holding and loweringmechanism to the shaft 12, and therefore to the screw. in respect tolowering movement; when desired. This means includes :1 normallyspring-disengaged and mamuilly-engageable clutch between the holdin; andlowering means of the shaft 12. Specifically the worm wheel is providedwith a crown of ratchet teeth 47, adapted to be engaged by a ring ofcorresponding teeth 48 on the depending rim of a clutch disk 49, whichis engaged with ribs 50 on an upper part of the shaft 12 so as to bemovable longitudinally thereon into and out of engagement with the teeth47 while held againstrotation relatively to the shaft. A spring 51,interposed between the clutch member 49 and the worm wheel 31, normallyholds the clutch element separated. Thus far the clutch is like thatdisclosed in the Kopf & Schwerin patent, but improved means are providedfor its manual operation.

In the present construction the upper end portion of the shaft isdrilled with a longitudinal bore or passage 52, which extends from theupper end to a point within the worm whee-l. A transverse bore orpassage 53 is also formed in the shaft intersecting the bore 52. Anoperating button projects at the top of the frame annex 16 and has astem 55 which passes through an opening in a top plug 56 and downwardinto the longitudinal passage 52 in the shaft. This stem has atransverse hole through it, through which and through the passage 58 across-pin 57 is inserted with its ends projecting at opposite sides ofthe shaft. The

ends of the pin rest upon the top of the longitudinally movable clutchmember 51, and the pin is movable transversely to itself in the passage53, which is considerably larger than the pin. The pin consequentlyforms the intermediary between the plunger 55 and the clutch member 49,so that downward pressure of the hand upon the button 54 will engage theclutch member 49 with the clutch teeth 47. When the hand is removed, thepressure of the spring 51 automatically raises the clutch member 49 andthe plunger. This construction is very simple and is more serviceablethan the construction disclosed in the Kopt & Schwerin patent, whereinthe yoke there employed straddling the end of the shaft would sometimesbecome deranged. The projecting ends of the cross-pin 57 may lie in acircular depression 58 in the top of the. clutch member 49, which willpreventendwise displace ment of the pin.

What I claim as new is:

A lifting jack in which there is a steeppitch lilting screw, a shaftgeared to said screw, holding; and lowering mechanism and a'rotarylowering handle, an automatic overrunning clutch between said mechanismand shaft, and a manually operatable clutch hav ing a spring-disengagedmember movable longitudinally of the shaft whereby the lowering meanscan be coupled to the shaft for positive lowering when desired,characterized by said shaft having intersecting longitudinal transversepassages in its end portion, an operating button having its stem workingin the longitudinal passage of the shaft, and a cross-pin movablelaterally to itself in the transverse passage and acting as theintermediary between said stem and the manually-operatable clutchmember.

' FRANK H. SCHVJER-IN.

